Embed eSignatures
into your workflow.
- Free to test
- Fast to deploy
- Powerful & secure
Take advantage of airSlate SignNow’s eSignature API and streamline your document workflows
Brandable eSignature solution
Customize our eSignature API with your company’s branding.
Sandbox account
Test the service for free with the developer sandbox.
Quick setup
Detailed API documentation and clear coding examples ensure an excellent developer experience.
High success rate
Enjoy superior app performance with our 24/7 API monitoring.
Flexible eSignature API for any use case and industry
What our customers say about our eSignature API

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$300/month
100 docs/month
Getting Started with the airSlate SignNow API course
Learn moreFAQs
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What is an eSignature API?
An eSignature API (Electronic Signature API) is a programming interface that allows developers to integrate electronic signature functionality into their applications, websites, or workflows. This enables users to digitally sign, send, and manage documents directly within the software they use, providing a more seamless and custom user experience. -
Is eSignature legally binding?
Yes, electronic signatures are legally binding in most countries and often carry the same weight as handwritten signatures. Look for digital signature API providers that comply with local laws and regulations like the ESIGN Act and UETA for the United States and eIDAS for Europe. Also look for detailed audit trails and tamper proof logs to ensure enforceability. -
How much does eSignature API cost?
Paid plans start at $2 per invite for 500 invites and drop to $1.20 per invite for 5,000 invites — a 60-75% savings compared to the leading eSignature API provider. Unlike competitors, airSlate SignNow includes embedded signing in all plans, while others restrict this essential feature to enterprise-level offerings. -
How to generate an api key?
To generate an API key, log in to the airSlate SignNow API and create a new application. This will give you a Client ID and Client Secret, which act as your API credentials. Next, use these credentials to request an OAuth 2.0 access token via the POST /oauth2/token endpoint. The access token you receive is used to authenticate your API requests. -
How many API calls can I make in development mode?
In development mode, you can make up to 500 API requests per hour per application. Additionally, there is a limit of 500 signature invites per account. This means that while each application can independently make 500 requests per hour, the total number of signature invites you can send across all applications under a single account is limited to 500. -
Can I customize the signer experience?
Yes, most eSign APIs offer the ability to customize logos, colors, and some messages. In addition to basic branding and customization features, more mature eSign API providers allow developers to fully customize the end-to-end signer experience with the ability to customize the signer workflow for each step of the process. -
Are there any hidden costs, such as additional fees for advanced features (e.g., webhooks, custom branding)?
Unlike other digital signature API providers, airSlate SignNow includes essential features like branding, event notifications, document collaboration, bulk sending, attachments, custom workflows, and multi-channel delivery in all API plans — without hidden costs or tiered restrictions. -
Can I send signature requests in bulk?
Yes! Upload a document, turn it into a template, and add fillable fields. Next, you’ll need to have a CSV file with a list of email addresses to send your template to. Indicate a folder to store the signed documents. Use the endpoint POST /template/@{{document_id}}/bulkinvite where @{{doument_id}} is the id of the template for sending bulk invites. -
How can I cancel a signature invite sent via eSignature API?
Signature invites can be canceled before recipients sign a document. To cancel an invite, use the PUT document/@{{document_id}}fieldinvitecancel endpoint. If some recipient(s) have already signed the document, their signature(s) will remain. The other signers will no longer be able to open the document.
Follow these simple steps to test the eSignature API:
- Create a Sandbox account. Submit your email address in the quick form to register.
- Validate your account. Follow the link in the email to proceed with the registration.
- Access Developer Sandbox. Provide a password to access your developer environment.
- Get your credentials. Go to Keys -> Test App to find your account credentials.
- Generate a Bearer Token. Use Postman or any Client that supports API requests to create and validate your Bearer Token.
- Test eSignature. Explore airSlate SignNow’s capabilities and evaluate the eSignature API.
These 6 simple steps will help you embed eSignatures into your application. Create, send, and eSign documents directly from your app. Try out our robust eSignature capabilities and compare airSlate SignNow API vs DocuSign API!
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Why choose our eSignature API
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Why choose airSlate SignNow’s eSignature API?:
- Free to test and easy to deploy
- SDKs for popular languages
- Customizable for any workflow
- Industry-leading security & compliance